History is there to teach us, but some choose to ignore it.
In June of 1941, the Germans invaded Russia, with whom they had both political and economic pacts. As they crossed the Western borders, the Russian people were actually pleased to see them, and I believe they even waved welcoming flags. They were eager to be rid of the oppressive Russian regime, and saw the Germans as their saviours.
So, how did the Germans react to this friendliness? In typical German fashion; they shot them!
They ended-up slaughtering Millions of civilians, as well as 3.3 Million Russian prisoners of war. After the shock, the Russians soon organised themselves, and the Germans were made to retreat.
In present day Russia, the civilians are deprived of reliable news, and refuse to believe that their own troops (sons) would go into Ukraine to bomb and kill. They proudly declare that 'the Ukrainians are our friends and neighbours, and Putin would NEVER do that'. I wonder if the Germans said the same about Hitler in 1941?
If one wishes to win 'hearts and minds' it's better to be nice to whoever you are invading; not slaughter them. Had the Russians recently entered Ukraine with parcels of Vodka, food, and warm clothing, people might have welcomed them. They might even have tolerated a change of government had it promised investment, stability, and prosperity.
The best way to alienate people is to mimic the German Unternehmen Barbarossa, and destroy and slaughter everything in your path.
The Russians, more than anyone, should have realised that!